Our primary mission in establishing the Familial Breast Cancer Resource is to reduce the incidence, morbidity and mortality of breast cancer. To this end, the resource will be used to identify and study genetic markers of breast cancer susceptibility, and to offer high-risk women participation in cancer screening and prevention trials. Index cases of familial breast cancer are identified from our own tumor bank, physician referral, direct media solicitation, screening of mammography reports, and other sources. Accruals have exceeded our original projections substantially. The database currently includes 223 families representing 12,137 individuals, including 707 members with a history of breast cancer. Data collection includes well-documented degrees expanded to include second order relatives of all breast cancer cases. Data items include demographic and contact information as well as clinical information on all cancers, and all benign breast conditions. During the next funding period we propose to place additional emphasis on review and verification of clinical data and on recruitment of Hispanic families. There is a well-established cooperative relationship between the resource and local breast cancer trials (e.g. NSABP Breast Cancer Prevention Trial) so that trial participants with a positive family history are referred to the resource and the resource refers interested high risk patients to the trial. In addition to the databases, the resource also includes tissue banks. After obtaining informed consent, blood samples are obtained from key members of families with 3 or more affected members for banking as cryopreserved peripheral blood lymphocytes (PBL's) and frozen serum. The bank currently contains 113 PBL and serum samples representing 30 families. An additional 300 individuals are already targeted but not yet drawn. Procedures for handling informed consents and drawing bloods, both locally and out of town, for processing bloods, as well as all of the associated computer inventories and tracking systems, are well- established. We propose to continue this activity during the next funding period. Additionally, for affected members, we will retrieve archival tissue samples. In Project 4 of this application we propose to use DNA from banked PBL's to examine several tumor suppressor genes implicated in both hereditary and sporadic breast cancer.